The present invention relates to an air bag for use in a passenger safety restraint system and more particularly to an air bag folded in a manner to enhance its operation and improve occupant safety. In addition, the present invention finds specific application with vehicle safety air bags adapted to protect the passenger and middle occupant.
Air bags have been proposed and used as part of passenger restraint systems which automatically deploy in emergency crash conditions. The air bags are typically stored in a deflated, folded condition in a location within the passenger compartment such as the instrument panel. During the crash and in response to a crash sensor of known variety, an inflation medium such as compressed gas or gas generator or combination of the two is actuated to communicate inflation gas to the air bag. The air bag softens or at least cushions the motion of the occupant thereby protecting same from serious injury.
The prior art teaches various types of folding or rolling techniques. One such technique which incorporates lateral folds within an air bag is illustrated in U.S. Pat. No. 4,235,453. Another patent utilizing what is called a "bubble roll" is shown in U.S. Pat. No. 3,748,477. Modern air bag systems propose placing the air bag within a housing or cavity (located in the instrument panel), having a transverse width significantly smaller than the width of the inflated passenger side air bag. As such, it is important to fold or position the air bag within such narrow opening in a manner that upon deployment the air bag can achieve its fully inflated width in an efficient manner. The present invention improves upon the technique shown in U.S. Pat. No. 3,748,477 by achieving a narrow folded diameter sufficient to fit within the narrow reaction can or housing while still permitting the efficient inflation thereof.
Accordingly, the invention comprises: an air bag and method of folding same such that its subsequent inflation volume increases in a manner so that it remains positively pressurized and provides a means to protect an occupant of a motor vehicle. The air bag having a deflated, rolled/folded condition and stored within a narrow opening in the passenger compartment of the vehicle and having an inflated unrolled/unfolded condition achieving a size substantially larger than the width of the opening. The air bag comprising: a main panel; and two side panels having a major oblong portion and first narrow portion, the main panel sewn to the side panels to form the air bag. The main panel define a top portion, front portion and bottom portion, with the ends of the top and bottom portions generally opposite the front portion that are narrowed to define a narrow neck portion. The air bag, as a result of the method used to fold same including a laterally outward extending first fold formed generally along a part of the bottom portion; a laterally outward extending second fold formed in the main panel proximate the top and front portions to permit the top portion and bottom portions to reside as at least partially aligned top and bottom layers of air bag material. In addition, the bag includes folding means for reducing the width dimension of the air bag to approximate the width of the neck portion, including a plurality of generally fore-aft extending folds, such that the air bag achieves a partially folded condition, having generally rectangular shaped with the neck portion at one end thereof, the plurality of folds formed of the air bag material between top and bottom layers; a rolled portion of air bag material formed starting at an end of the plurality of folds opposite the neck portion; the unrolled portion of the partially folded condition forming a flap being itself partially or totally folded over a portion of the rolled portion so as to form an upper surface covering part or all of the rolled portion when deflated, the flap forming a transitory envelope or air sack upon inflation, wherein upon inflation the envelope urges the rolled portion to unroll in a direction toward an occupant drawing material from the rolled portion to prevent same from forceably contacting the occupant. Various method claims define the steps used to achieve an air bag of the type described above.
Many other objects and purposes of the invention will be clear from the following detailed description of the drawings.